Age is a significant risk factor in cataract formation. Such cataracts that develop in the elderly are referred to as senile cataracts. Cataracts can also be caused by trauma or as by-products of disease, or be congenital in nature. Cataracts are also thought to result from the use of certain drugs, such as alcohol [see J. J. Harding and R. Van Heyningen, British Journal of Ophthalmology 72:809-814 (1988)], phenothiazine drugs and haloperidol [see N. E. Isaac et al., Arch Ophthalmol 109:256-260 (1991)], and allopurinol [see W. K. Clair et al., British Journal of Ophthalmology 73:173-176 (1989)].
In any type of cataract, the opacification (a molecular process of devitrification) of the crystalline lens is the chief cause of the visual loss in individuals with this condition. It is therefore desirable to find a method of reducing and/or preventing cataracts. Certain drugs are thought to have a protective or beneficial effect on the development of cataracts, such as aspirin, aspirin-like analgesics (paracetamol, ibuprofen), and cyclopenthiazide (a diuretic). See J. J. Harding et al., Acta Ophthalmologica 67:518-524 (1989); J. J. Harding and R. Van Heyningen, British Journal of Ophthalmology 2:809-814 (1988); J. M. Seddon et al., Arch Ophthalmol 109:252-255 (1991); B. E. K. Klein et al., Diabetes Care 10:495-499 (1987); and H. Cheng, British Journal of Ophthalmology 76:257 (1992). Although several drugs are currently used or under investigation for such reduction or protection, a need continues to exist for an efficacious method of reducing and/or preventing cataract formation which can readily be used without adverse side effects on humans.